Controlling apparatus for elevators.



CONTROLLING APPARATUS FOR ELEVATORS.

W. C. STRANG.

APPLICATION FILED DEC. 4, I912.

Patented July 11, 1916-.

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' APPLICATION FILED DEC. 4. I912. 1,1 90,969.

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WITNESSES:

I INVENTOR W 7722162,: gm W v nrrofin t Patentd July 11, 1916.

w. c. STRANG. CONTROLLING APPARATUS FOR ELEVATORS.

APPLICATION FILED DEC. 4, I912.

Patented July 11, 1916.

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CONTROLLING APPARATU FOR ELEVATORS.

APPLICATION FILED DEC. 4, 1912.

1,1 90,969. Patented July 11, 1916.

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UNITED STATES PATENT orFIo WALTER C. STRANG, OF YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY,

OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

CONTROLLING APPARATUS FOR ELEVATORS.

Specification of Letters Patent.

Patented July 11, 1916.

Application flled necember 4, 1912. Serial No. 734,828.

To all whom it may concern.

Be it known that I, WALTER C. STRANG, a citizen of the United States, residing in Yonkers, in the county of \Vestchester and State of New York, have invented a new and useful Improvement in Controlling Apparatus for Elevators, of which the following is a specification.

My invention relates to a system of automatic control for elevators, and has for an object the provision of simple, practical and efiicient means for controlling the operation of power driven hoisting apparatus.

Another object of the invention is the provision of an automatic governing device for controlling the speed of an elevator car.

Another object is the provision of a device for controlling the acceleration and deceleration of an elevator car under all condi tions.

A further object of the invention is the provision of an inertia controlling device for preventing the too sudden starting, stopping and change in speed of an elevator car under all conditions of load and speed.

' Other objects will'appear hereinafter, the novel combinations of elements being pointed out in the appended claims.

In the operation of .a modern elevator system, one of the most diflicult obstacles to overcome is the proper starting and stopping of an elevator car, as Well as to effect a proper variation in speed from fast to slow, or from slow to fast while the car is traveling in either direction. It is readily seen that it is out of the duestion to leave the entire control of an elevator to the operator in the car, since as a rule the operator is indifferent or careless, and it would he positively unsafe to leave the running of the car to his care, unless certain safeguards were not first provided to limit his control. in other words the operation of the modern elevator system is made automatic as far as it is possible to do so, so as to take away from the operator all control of the car except the power to start, stop and reverse the same. As the height of buildings is becoming greater every day and the speed of elevators is being increased to meet the new conditions, the proper control of these high. speed elevators presents a problem of no small importance, for, While it is a comparatively easy matter to control a slow moving elevator car, it is much more diflicult satisfactorily to control a high speed elevator. It is well known that the human body may be accelerated from rest to any desired speed providing the rate of acceleration does not exceed a predetermined amount, otherwise, great discomfort is pro-' type, if the valve be closed too quicklywith. a descending car, the latter is: brought suddenly to rest while the inertia of the unbalanced load produces an enormous pressure within the plunger cylinder, which is in itself a source of great danger not to speak of the efiect on the passengers in the car. if the valve he suddenly closed with an ascending car, the momentum of the unbalanced load causes the car to continue in an upward direction, until the same is brought to rest by gravity, the plunger separating from the water in the cylinder. As soon the car comes to rest it immediately falls hack a ain. and the plunger strikes the incompressible water a blow and is at once stopped in its movement with a violent shook. Various valves and other mechanism have been devised from time to time to overcome these undesirable features, but only meet with indifierent success, and such devices are as arule expensive and complicated, and in general are not to he I controlled switches which are generally arranged to regulate the amount of current passing in the motor armature and field so as, to efiect a gradual start and stop- If these switches be adjusted so as to effect the proper acceleration or deceleration of the elevator car with a predetermined load, any variation in load will tend to change the rate of acceleration or deceleration so In the drawings accompanying this specification, Figure 1 represents a hydraulic elevator system containing an embodiment of my invention; Fig. 2 is an elevational view in part section of an inertia governor arranged to efl'e'ct the desired control of the elevator; Fig. 3 is an electric traction elevator system containing an embodiment of my invention; Fig. 4 is a detail view in part section of the governor device shown in Fig. 3; Fig. 5 is a'diagrammatic representation of a traction elevator'containin'g an embodiment of my invention in a modified form; Fig.6 is a detail sectional view of the double acting dashpot device shown in Fig. 5; Fig. 7 is a wiring diagram of the electrical circuits associated with the elevator systems shown in Figs. 3 and 5.

Similar reference characters denote similar parts in all the figures.

Referring to Fi s. 1 and 2, I show a typical'plunger "hy raulic elevator comprising an elevator car G partially counterbalanced by a weight W and carried upon the upper end of a plunger P, which is adapted to reciprocate in the plunger cylinder A. A main valveV is connected by the to-andfrom pipe 6 to the cylinder A and eii'ects the upward and downward movement of the elevator car by admitting water to or exhausting water from the cylinder A through the sup ly and exhaust p'ipesS and Erespeetive y. The main va ve' V is controlledby the pilot valve B, which in turn is operated from the elevator .car by any one of several well 'known methods such as the handrope H and connected lever 7.

Thus far the description will apply to any standard plunger elevator. In carrying out my invention, a governor G is connected through a coupling 2 to the overhead sheave '1 which always-rotates at thesame speed as that of the car. The governor G operates a lever 8 which is connected to a valve 410- catedbetween a'tank T anda pipe 5. The latter connects with the to-and-from pipe 6 of the elevator. The tank T is open atthe top and is always filled or partially filled to turn thereon.

with water and maintained in that condition by a supply pipe 9 and floatball-valve connected thereto; an overflow pipe 10 being provided near the top of the tank. The valve 4 is preferably a balanced valve as shown and the same controls the fluid connection between the tank T and plunger cylinder A. As seen in Fig. 2, the governor G comprises a shaft 11 which -is carried by suitable brackets near either end and which supports a fly wheel 12 free The latter contains a V- shaped notch- 13 in one hub adapted to receive a corresponding V-shaped projection 15 in a sleeve 14 which is positively driven by the shaft ll'through a feather 16, but has, a bodily movement thereon. A yoked lever 18 is pivoted at 21 to a bracket 20 and straddles the sleeve 14, and is operatively connected thereto by means of a pair of oppositely disposed pins such as 19 which enter a circumferential groove in the said sleeve. A pair of nuts 17 are threaded upon the shaft 11 adjacent the sleeve 14 and limit the bodily movement of the latter thereon. The upper end of the yoked lever .18 is connected by a slot and pin connection to a rod 22 carrying upon it a valve 25 adapted to move in a cylinder 26 tightly closed'at its right hand end. The piston 25 the piston having a freedom of movement in a right hand direction by reason of the check valve 27 but being restricted in-its movement in a left hand direction to an extent which may be controlled or regulated -As the shaft 11 is rotated, the sleeve -14 is rotated with it and owing tothe action of the inclined planes comprising the sleeve wedge 15 and V-slot 13 in the fly wheel hub,

the fly wheel is also rotated. If, now, the speed of the shaft 11 be abruptly reduced,

thefly wheel, owing to its momentum, will tend to resist this reduction of speed and' hence there will be .a relative rotary movement between the fly wheel and sleeve 14, which latter, asbefore pointed out, must rotate with the shaft and at the same speed thereof. ,Itis at once apparent that any relative change in speed between thesleeve and fly wheel will. cause the inclined faces of the sleeve wedge J to ride up out of the notchin the fly.wheel hub, thereby moving the sleeve bodily in a right handndirection along theshaft 11 and thus operating the dashpot rod 22 and valve 25. This movement of the sleeve is opposed by the spring 24 but not by the dashpotowing to the relief valve 27. As the momentum of the fly wheel is over'comeand its speed falls to that of the shaft 11, the spring 24 is enabled againfto seat the sleeve wedge into the fly wheel notch, thereby moving the rod 22 and dashpot valve 25 to the left, the rod being controlled -in this movement by reason of the vacuum set up in the dashpot cylinder under control of the pet cock 28. If the speed of the shaft be increased beyond a certain predetermined rate the inertia of the fly wheel will cause it to lag behind the shaft and sleeve and the rod 22 will, as before, be-moved in the same direction and controlled in an opposite direction by the dashpot. The nuts 17 on the shaft 11 prevent the sleeve from moving too far away from the'fiy wheel, the nuts 23 on the rod 22 control the sensitiveness of the governor, while the pet cock 28 controls the movement 1 of the rod' 22.

inder. Under these circumstances the car.

will tend suddenly to cometo rest being abruptly halted in its downward travel by reason of the imprisoned and incompressible iiuid under the plunger. At this time, however, the tendency to effect a rapid change of speed is immediately felt by the governor, the momentum of the fly wheel acting to open the valve 4 and establish a communication between the tank T and the plunger cylinder A through the pipe or riser 5. The water in the plunger cylinder may now back up into the tank T, thereby relieving the pressure under the plunger and check'the tendency of a too rapid-stop of the car. In the meanwhile the fly wheel of the governor will lose momentum and the valve i gradually close again, its speed of closing being controlled by the dashpot. As the valve 4 is gradually closed the water flowing from the plunger cylinder into the tank T will be gradually cut off and the elevator car will smoothly and gently come-to rest.

In a similar manner if the car operator attempts to start upwardly again too sud. denly the rate of speed change acting through the governor will move the valve 4 so as to open a communication between the to-and-from .pipe 6 and the tank T and a portion of the supply will by-pass into the tank and thus prevent a too sudden start and acceleration of the car due to a too rapid entry of water under the plunger cylinder.

The governor may' be so adjusted by the means furnished for that purpose so that the same will not act when the rate of starting and stopping or varying the speed While running is within proper limits, but it will act under a predetermined speed change under all conditions. 7

Referring to Fig. 3, I there show a traction drive electric elevator in which an electric motor M is adapted to drive a sheave D in frictional engagement with a plurality of cables F connected at opposite ends to an elevator car C and counterbalance weight \V. The governor G may be driven directly from the motor shaft as shown or by any other'part of the elevator apparatusfwhich operates synchronously with the elevator car. The governor G shown in Fig. 4 is substantially the same as that shown in Fig. 2, only in the present instance the governor rod 22 is connected to a lever 29 which carries upon one end, but insulated therefrom, a pair of contact arms 30 and 31 adapted to move over'a series of stationary contacts of different lengths such as 32, 33, 34 and 35, 36, 37, respectively, which may be connected to corresponding conductors or wires associated with the controlling'system of the elevator and which will be pointed out later in connection with Fig. 7. This governor may be provided with a dashpot similar to that shown in Fig. 2,.and it is preferably so equipped.

In Fig. 5 is shown an electric traction elevator in which the governor or speed controlling device is arranged in a different form than that already discussed and is carried directly upon the elevator car. In this instance the overnor (see Fig. 7) comprlses a long ever 38 pivoted at an intermediate point 39 to the car C and having an adjustable weight 42 near one end and a compression spring 40 near the other end which bears against a fixed stop 41. and tends to counteract the weight 42,. A lever *l-l is secured to the lever 33 and has a pin thereon which lies in a U-shaped member 46 carrying a pair of contact arms 30 and 31. A doubleacting dashpot i3 is hung from the car by a bracket 49 and is operatively connected by the piston rod 48 to a suitable point on the lever. This dashpot is shown in detail in Fig. 6, and comprises a piston which normally occupies a position midway between the closed ends of the dashpot cylinder.- Both ends of the dashpot cylinder are closed air tight and areprovided with check valves 52 and 53 opening outwardly and pet cocks 54 and 55. At the centerot pressure into the dashpot are a series of elongated holes or slots 51 which are wider than the thickness of the piston 50. The operation of the governor shown in Figs. 3 and4 is similar to that already described in connection with Figs. 1 and 2, only in Figs. 3 and 4, the governor moves the contact arms 30 and 31 over their respective stationary contacts in a left hand direction and back to center position as shown. h

The operation of the governor device of Fig. 5, while embodying substantially the same principle as that of the inertia governors already described, operates in a somewhat different manner. The lever 38 is, under normal conditions, equilibrated by the opposing actions of the weight 42 and the spring 40. If the car is at rest or traveling at a constant speed this lever will remain in equilibrium no matter what the speed may be. If, however, the'car undergoes a change of speed, say from a high speed in a downward direction to a slower speed, the momentum of the weight 42 will tend to rock the lever about its pivot in an anti-clockwise direction and thereby move the contact arms 30 and- 31 in a clockwise direction over the stationary contacts associated therewith. If the car be suddenly started upwardly from a position of rest, the weight 42 will tend to hang back, due to its inertia, with the result just pointed out, while if the car be suddenly started downward the weight will tend to lose in effective weight and the spring 46 will be enabled to rock the lever 38 in a clockwise direction, again effecting a movement of the contact arms, only at this time in the opposite direction. The dash pot permits the inltlalmovement of the lever without any retarding action owing to the arrangement of the check valves 52 and 53, but it will retard the return of the lever to equilibrated position for both directions of movement an amount depending upon the extent of opening of the pet cocks 54 and 55. While.

the contact-carrying lever 46 of Figs. 5 and 7 is capable of movement in both directions from a central position, and the contact carrying lever 2901? Figs. 3 and 4 only moves 1n one dlrection past central position, the control of the electrical circuits associated with these contacts 32, 33, 34 and 35, 36, is similarly eflected.

In Fig. 7, I show a system of electrical .circuits well adapted to an electric elevator embodying my invention, and which may be used with either of the types of inertia governors as shown in Figs. 3 or 5. The starting, stopping and reversing of the elevator motor M is effected from -the car switch 47 which is operatively connected to the reversing switches 5'6 and 57 which operate to establish the roper motor armature,

held and brake circuits n a well known way from the source of current supply designated by and A sectional resistance 62, 62, 62 1s used in starting and is conforms the same functions in stopping the motor, being connected across the armature terminals when both reversing switches are in stopping position, the short-circuiting of the stopping resistance being effected by the stopping magnets 63, 64 and 65, which are also connected to the motor armature terminals in stopping and operate gradually to short-circuit the sections of stopping resistance according to the varying counterelectro-motive force of the motor in stopping, thereby eiiecting a variable dynamic brake action which is assisted by the usual friction brake 58. A resistance 69 alone is never out out of the stopping circuit and by its presence it prevents damage to the motor by any excessive dynamic brake current. It will be observed that one terminal of each accelerating and stopping magnet is connected through the governorv contacts 37, 36, 35 and 32, 33, 34, respectively, and hence, by controlling the circuits to these various magnets by means of the inertia governor, the control of the elevator may be effected by the governor throughout its every movement. For example, let us assume that the elevator car is lightly loaded and the operator in the car desires to go up. Should the motor tend to accelerate too rapidly and the accelerating magnets attempt to short circuit the starting resistance without allowing suiiicient time for the car gradually to acquire speed, the rate of change of car speed will be such that the governor will move the contact arm 31 off of more or less of the contacts 37, 36 and 35 in successive order, depending upon the rate of speed change, thereby open circuiting more or less of the accelerating magnets 66, 67 or 68 and thus introducing all, or a portion of, the startin resistance back into the armature circuit an checking the tendency of the elevator car to attain full speed at an excessive rate of acceleration. If the car be traveling at full speed and it is desired to stop the same, the dynamic brake circuit comprising the sectional resistances 61, v61, 61, is closed across tact arm 30 so as to open circuit one or more of the stoppin magnets, thereby reinserting more or less 0 the stopping resistance in the armature circult and m th1s manner conposition and hence controls in a measure the action of the governor and prevents a too sudden or violent movement of the same while at'the same time without interfering with its proper functions.

The governor device will respond instantly to excessive speed changes of the car or motor under all conditions met in practice, and

affords a simple and effective means for absolutely preventing too quick a start or stop or change of speed-for both directions of travel, thereby'guarding against any undue or excessive strain throughout all parts of the hoisting apparatus and preventing any discomfort to the passengers caused by excessive speed changes .The particular elevator apparatus shown in the accompanying drawings is merely typical and was chosen for the purpose of illustrating the invention and its operation as clearly as possible, and I desire not to be limited to the specificarrangement and construction of parts herein set forth, since it is obvious that my invention is applicable to any and all types of power driven elevators or hoisting apparatus of all descriptions and furth'ermorethe same may be used to advantage with any. apparatus in which it is desired to control the rate or" speed changes of a power driven movable member of which an elevator car is but one example.

I believe it is broadly new automatically to control an elevator car by means whose action is governed bythe rate of speed changes to which the elevator may be subjected.

What I claim, and desire to secure by Letters Patent of the United States is 1. In an electric elevator, the combination of a hoisting motor, means for varying the current in the said motor in starting and stopping, and additional means dependent for its operation upon the rate of speed variation of the motor for controlling the current in' said motorboth in starting andstopping.

2. In an elevator, the combination of a car, an electric motor operatively connected thereto, means for controlling the motor, and additional means -'-operative upon excessiv'e speed variation in the said car for reducing the current flow to the motor.

3. In an elevator, the combination of a car, an electric motor 0 eratively connected thereto, a starting an dynamic stopping resistance for the motor, means for controlling the said resistances, and means de pendentupon the rate of speed change in the said car for controlling the saidresist 'ance controlling means. i

A; In an elevator, the-combination with a vertically movable load carrying device, an electric motor for operating the device,

means for controlling the speed of the motor, an inertia controlled means for controlling the rate of speed variation of the motor both in starting and stopping.

, 5. In an elevator, the combination with a vertically movable load carrying device, an electric motor for operating the device, means for controlling the speed of the motor, and additional motor controlling means independent of the counter-electromotive force of the motor for controlling the speed of the motor both in starting and stopping.

6. In an elevator, the combination with a vertically movable load carrying device, an electric motor for operating the device, a resistance in a circuit of the motor, means for cutting out said resistance in starting the motor, and inertia controlled means for reinserting said resistance upon. excessive acceleration of the motor. I

' 7. In an elevator, the combination with an electric hoisting motor, .a resistance for controlling the acceleration of the motor, a resistance for controlling the deceleration of the motor, and means dependent for its operation upon the rate of speed change of the motor for varying said resistances.

8. In an elevator, the combination with an electric hoisting motor, a resistance for.

sive device controlling the resistance, a

stopping resistance in acircuit of the motor, an electroresponsive device controlling the stopping reslstance, and means dependent upon the rate of change in speed of the motor for controlling said electro-respon sive devices.

10. In an elevator, the combination with an electric hoisting motor, a starting resistance in a circuit of the motor, an electroresponsive device controlling the resistance, a stopping resistance 1n a clrcuit of the motor, an electroresponsive device controlling the stopping resistance, and inertia controlled means for controlling said electroresponsive devices. I

11. In an elevator, the combination with an electric hoisting motor, a starting resistance in a circuit of the motor, an electroresponsive device controlling the resistance, a stopping resistance in a circuit of the motor, an electroresponsive device controlling the stopping resistance, and an equilibrated lever responsive to variations in for effecting the-starting and stopping of the motor in accordance with the load on the motor, and additional automatic means for modifying the operation of said starting and stopping means in accordance with the. rate of speed variation of the motor.

13. In an electric elevator, the combina tion with an electric hoisting motor, a starting resistance in series with the motor armature, a' stopping resistance in parallel with the motor armature, a series of switches for controlling said starting and sto ping resistance, means for operating .sai .switches to effect the starting and stopping of the motor, and additional means controlled by the rate of change in speed of the car for operating said switches. I

14. A vertically movable elevator car, an electric motor operatively connected therewith, a resistance in the motor circuit for controlling its speed, and means dependent upon the rate of speed change of the motor for controlling said resistance.

15. In an elevator, the combination with an electric motor, a resistance in a circuit of the motor, means for cuttlng out sald-resistance 1n starting the motor, and mertla controlled means for reinserting said resistance into the motor circuit in the event of an excessive motor acceleration.

- 16. In an elevator, the combination with an electric motor, a resistance in a circuit of the motor, means for cutting out said re tion of the motor for reinserting said resist-- ance in accordance with the rate of accelera tion.

In testimony whereof, ,I have signed my name to this specification in the presence of two subscribingwitnesses. a

WALTER c. STRANG.

Witnesses:

W. H. BRADY, JAMES G. BETHELL.

.sistance in starting the motor, and means 

